This invention relates to a reel for winding metallic wire such as steel cord and steel wire.
Heretofore, a reel of this type was composed of a flange 1 and a winding drum 2 joined into one piece by a plurality of weldings W between the end of the winding drum 2 and an inward cylindrical bulge la provided in the central portion of the flange 1 as shown in FIG. 7.
Normally, when continuously winding a metallic wire on a reel, since a tension is applied to the metallic wire, the wound up metallic wires tend to spread toward the flanges and a side pressure is applied on the inside of the flange and the side pressure is increased as the quantity of wire wound on the reel is increased. Thus, the right and left flanges tend to be bent toward the outside and the interval between the right and left flanges is increased. Since the metallic wire is wound while detecting the inside position of the inner faces of the right and left flanges and with the traverser traversing under the control of such detection, an extended interval between the flanges causes a variation in the traverse position, leading to deteriorated winding conditions of the metallic wire, causing broken wire and entanglements.
The bent and deformed reel is reused after correcting the condition of the flanges, but can be broken during correcting or winding, and the limit of the number of corrections has been at most three.
Further, since the increase of the flange interval has been considered to be due to the bending of the flange itself, to counteract the problem the thickness of the flange has been increased to increase the rigidity. This has made the reel heavier, leading to poor workability.
As a result of the study by inventors of the cause of outward bending of the flanges, it has been found that the outer radial portion of the flange itself is not bent, but the outer radial portion of the flange as a whole is bent outward around the part 3, where the material of the central part of the flange is bent inward to form the bulged part, as a fulcrum.
The reasons the bent part forms the fulcrum of the flange bending are the following two points:
One point is that since the inward bulge la of the flange is formed by pressing, the thickness of the flange material at the bent part 3 is decreased by about 20-25%, leading to decreased strength of the bent part. The other point is that the flange and the winding drum are fixed by welding only at the peripheral surfaces of the joint part.